Uxcell 5-Piece Fish Tank Bubble Maker Air Stone, 25mm, Gray Product Name : Aquarium Air Stone; Shaped : Round Design Material : Mineral, Plastic; Import Diameter : 2.5mm/0.1" Size(Approx.) : 2.5 x 4cm/1" x 1.6"(D*H); Color : Gray, Black Weight : 75g Package : 5 x Aquarium Air Stone